As used in the present application and claims, the term "utility power" applies to electrical power supplied at a level that corresponds with the power supplied by a local publicly or privately owned power generator. In North America, utility power is typically supplied at a voltage of about 110 or 220 VAC and a frequency of 60 hertz, and is available for use through power outlets of standard configuration. In other countries, utility power maybe supplied at other voltage levels and/or frequencies.
Although many types of electrical appliances, such as dishwasher and televisions, can remain plugged into the utility power source when not in use, there are certain types of electrical appliances that must and should be unplugged for safety reasons when not in use. One appliance of the latter type is an electric hair dryer, which is typically used in a bathroom or other area where water is present, and can present a significant safety hazard if left plugged into the utility power outlet when not in use. Other appliances of this type include electric curling irons and electric shavers. Manufacturers of such appliances typically attach a warning label or tag to the appliance advising the user to unplug the appliance when not in use. Such warning, however, is frequently forgotten or ignored. Inadvertent contact with water can and does present a significant hazard of personal injury including death by electrical shock, particularly to small children.
It is therefore a general object of the present invention to provide an alarm device for use in electrical appliances of the described character that automatically warns an operator or user to unplug the appliance when the appliance is turned off. Another and more specific objection of the invention is to provide an appliance alarm device of the described character that may be readily incorporated into appliances of conventional design and construction, that is economical to implement, and that cannot be readily defeated or rendered inoperative by a user.